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A104042
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Numerators of coefficients in expansion of x^-2*(1-exp(-2*x))^2.
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3
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4, -8, 28, -8, 248, -16, 508, -136, 584, -496, 16376, -16, 131056, -174752, 18724, -2056, 1048568, -1168, 4194296, -20336, 684784, -1945184, 67108856, -3856, 536870896, -715827872, 306783376, -19746976, 17179869152, -3198784, 8589934588, -134744072, 426829048, -91625968976
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OFFSET
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0,1
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COMMENTS
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Suggested by Bill Gosper's remarkable identity (in a posting to math-fun list, Apr 14 2005): Product_{ n >= 0 } tanh(2^n x)^(1/2^n) = (1-exp(-2*x))^2.
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LINKS
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MAPLE
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S:= series(x^(-2)*(1-exp(-2*x))^2, x, 34):
seq(numer(coeff(S, x, j)), j=0..31); # Robert Israel, Aug 12 2019
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MATHEMATICA
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Numerator[ CoefficientList[ Series[x^-2*(1 - E^(-2x))^2, {x, 0, 33}], x]] (* Robert G. Wilson v, Apr 20 2005 *)
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CROSSREFS
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KEYWORD
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sign,frac
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AUTHOR
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STATUS
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approved
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